Table 8.

Summary of environmental and non-diet lifestyle factors associated with nasopharyngeal carcinoma

Potential risk factor	Summary of results
Smoking/tobacco	Risk factor (passive or personal) [56,57,60,61,65,69,72] [S2,S3,S5,S9,S21]
	Potential association [78] [S30]
	Passive or personal smoking no association [66-68,70,71,89] [S1,S18,S183]
	Results inconclusive or association unclear [58,59,62-64,73,76,83,92,93,95,96] [S17,S22,S26,S184]
Cannabis and other drugs	Cannabis – unclear association [67]
	Betel nuts – no association [58,72,89]
	Betel nuts – result undocumented [S5]
Occupational exposures:
Wood dust and wood	Wood dust risk factor [60] [S184,S185]
	Wood dust – no clear associations [S186]
	Wood – no association [59,89]
	Wood cutting no association[71]
Smoke, fumes and dust	Inhalation of smoke and dust risk factor [59]
	Smoke, quarry, road or other dust risk factor [59]
	Fumes and smoke risk factors [73]
	Dust/exhaust risk factors [S187]
	Products of combustion risk factor if lengthy exposure [S18]
	Construction dust no association [59]
	Dust and/or fumes, smoke no association [64,73] [S18,S184]
	Wool and synthetic fibre dust no association [S188]
Formaldehyde and other chemicals	Chlorophenols risk factor [S189]
	Chemicals risk factors [73]
	Chemicals no association [S184]
	Chemical fumes inconclusive [64]
	Formaldehyde – no clear association [S186,S187]
	Formaldehyde no association [S184,S185]
	Bleaching agents, dyes and endotoxin no association[S188]
Solvents	Solvents no association [S185,S188]
	Solvents – impact inconclusive [76]
Heat	Potential risk factor [73]
	No association [S184]
Ventilation	Poor ventilation – results unclear [S21]
	No association [S22]
Overall occupation	Agricultural work potential risk factor [71]
	Occupational hazards risk factor [68]
	Occupation no association [58] [S17,S190]
	Occupation – result undocumented [S5]
	Occupational exposure to cotton dust, inks and potentially acids, bases and caustics risk factors [S188]
Home environment:
Wood dust and wood	Wood fuel risk factor [76,85]
Smoke and fumes	Exposure to cooking fumes through having no separate kitchen or a range without a chimney risk factor [93]
	Poor ventilation risk factor [85] [S1,S17]
	Poor ventilation no association [58]
	Domestic fumes – no consistent association [67]
	Soot and cooking fuel no association [58]
Water	Reservoir sourced water protective [91]
General dust and smoke	General smoke exposure risk factor [S1]
	General dust exposure no association [S1]
Family structure:
	Sibship size (particularly older siblings) risk factor; birth interval, maternal and paternal age no association [S191]
	Birth order – coming later is protective [S192]
	Marital status – no consistent association[63]
Age:
	Age – rate increases with age [S193]
	Age – increases into 30-50 year age groups [S17]
	Age – more NPC than expected in individuals aged 30-39 [S104]
	Age – peak in late adolescence/early adulthood (15-24) and then later in life (65-79 years) [S195]
Sex:
	Sex – more NPC in men [S17,S193,S194]
Geographic region and ethnicity:
	Country – eastern and southeastern Asian are the highest rate regions; China, Malaysia and Singapore countries of note [26]
	Ethnicity – rates higher in individuals with Native American ancestry than White or Hispanic [S196]
	Ethnicity – in individuals with White and Black ancestry higher rates than Chinese [S193]
	Ethnicity – mainland Chinese vs Taiwanese, association with NPC [S21]
	Ethnicity – higher risk in mainlanders than in Taiwanese [S17]
	Immigration – immigrants have higher NPC rates, particularly if they originate from North Africa, Southeast Asia and Asian Arab countries [S197]
Socio-demographic:
	Socioeconomic status – higher is a risk factor [58,85]
	Education – higher levels protective [60] [S3]
	Education – no consistent association [63]
	Education – no association [S190]

NPC – nasopharyngeal carcinoma

*References marked with letter S are available in the Online Supplementary Document.